Helpful guide. Assigning names to the two levers that help highlight how A is linear while B is nonlinear really makes driving this train feel more natural.

as a truck driver iv been experimenting with it and the various speed ranges for each gear.

Not used to low med high, jsut a low and high but it makes more sense now.

To keep running costs down I prefer to keep the RPMs below 800 (out of the yellow), this means i do most my up shifts when hitting 800ish. Up shifting to soon or skipping to many gears will cause your fluid coupling to stall and overheat your oil.

It is perfectly safe when down shifting to skip gears if you know what you are doing. But this is only useful when braking hard and reducing speed fast, say you are doing 65 and quickly reducing to 30 and then hitting an incline you may wanna go directly from 3 to 1 or whatever to keep power and momentum up.

Gearbox A will net you around 400ish rpm with each shift.
Gearbox B will net you around 200ish for 1 and 2, while 3 is like 600ish.
Results may vary depending on how the gears are mixed between boxes.

a couple things I noticed from my couple hauls I did with the DM3 so far:

While upshifting has to be done in the 800+ RPM range, if you're not reaching the "capped speed" then odds are you probably won't be able to keep increasing your speed and thus are probably better in your current gear (will usually happen on steep inclines with basically any kind of load)

While skipping gears is pretty safe when upshifting, you do NOT want to skip gears while downshifting, doing so will blow the powertrain within 2-5 seconds if you're above the Safe RPM of the gear you're downshifting to. Exception is downshifting once the locomotive is immobile

I currently need to do more tests to figure out exactly when the RPM are low enough to downshift but for Gearbox A, it seems like you're generally safe to downshift once your RPM falls below 700 while Gearbox B generally seems to require less than 500 RPM

Thanks for this guide, the DM3 gears make sense now. I'm a truck driver and thinking of the DM3's gear box as the gear stick on the left and the splitter on the right just makes so much more sense than the 1-1, 1-2, 2-1 etc. lists I've seen elsewhere.

1-1: 20
1-2: 15
1-3: 7.5
2-1: 12
2-2: 9
2-3: 4.5
3-1: 8
3-2: 6
3-3: 3

These are the gear ratios I have seen floating around on the net, not sure if they are 100% correct or from the current build of the game.

Thanks, I really appreciate you giving names to each of the positions of the two gearbox levers. That actually helps me more than just the diagram in the other DM3 guide that showed the positions of eight sequential gears. Much easier to work with when I can glance at the lever position and think ok, that's 2-H or 1-OD or what have you, rather than having to remember at what point in the sequence I am coming from and going to.

And no offense to the person who made the other guide. I appreciated that one too, it helped me get started. This one just helped me understand it a lot better. =)

Thanks. Simple and effective.

can someone just make a coherent video, squirrel can not do a tutorial video to save his life.

Or 1-1, 1-2, 2-1, 1-3, 3-1, 2-2, 3-1, 3-2, 2-3, 3-3 from lowest to highest as I understand it. You can skip gears. I usually just ignore 1-3 and 3-1 as those gears are too close to the others to be used practically.